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An easy and reliable way is presented to measure the duration of UV femtosecond laser pulses of λ < 200 nm. The used autocorrelation techniques are based on two-photon absorption (TPA) in different TPA media, especially calcium fluoride (CaF). For 197 nm, the laser-pulse energy transmission and the laser-induced fluorescence of self-trapped excitons at 278 nm are applied. Both methods yield nearly the same second-order autocorrelation functions allowing to analyze the investigated laser pulse and obtain its duration of $$(350\pm10)$$ fs. [ABSTRACT FROM AUTHOR]

Femtosecond (fs) laser pulses at variable delay times allowed us to track the fast non-radiative transitions between the manifold of highly excited $\mathrm{M}_{\mathrm{Na}}^{**}$ states to the lower lying fluorescent $\mathrm{M}_{\mathrm{Na}}^{*}$ state in CaF. Two distinct $\mathrm{M}_{\mathrm{Na}}^{**}$ states of the manifold at 3.16 eV ( $\mathrm{M}_{\mathrm{Na}2}^{**}$) and 4.73 eV ( $\mathrm{M}_{\mathrm{Na}3}^{**}$) were populated using the second (SH) and third harmonics (TH) of fs laser light at 785 nm. The population kinetics of the fluorescent $\mathrm{M}_{\mathrm{Na}}^{*}$ state in the 2 eV excitation energy range was revealed by depleting its fluorescence centered at 740 nm using fundamental near infrared (NIR) fs laser pulses. The related time constants for $\mathrm{M}_{\mathrm{Na}2,3}^{**}{\sim}{>} \mathrm{M}_{\mathrm{Na}}^{*}$ relaxation amounted to 1.0±0.14 ps and 3.0±0.3 ps upon SH and TH excitation, respectively. [ABSTRACT FROM AUTHOR]

A new setup for fast wavelength switching of an Yb:YAG disk laser uses a lithium niobate Lyot filter. It is modeled by the Jones matrix formalism and it is tested experimentally. Applying a high voltage to the Lyot filter leads to stepwise wavelength switching of the laser with a minimum step size of 91 pm determined by the intra-cavity etalon ensuring longitudinal single-mode operation. The maximum step size achieved with the current driving electronics amounts to 0.6 nm at 500 Hz switching frequency. This setup shows high spatial and temporal laser beam stabilities. [ABSTRACT FROM AUTHOR]